How to make curved windows using Archimesh?
I suppose one to go about this is to simply use modifiers.
Position the window group about where it should be, and add a subdivision surface modifier set to simple (this will avoid unwanted deformation of the shape and allow the next modifier to work)), followed by simple deform. set to bend to the window object inside of the window group empty.

Adjust the angle of the simple deform, and adjust position as needed, and you should end up with something like this result: